1. Field of the Invention
This invention relates to a heater head for a multi-cylinder hot gas engine of the type having regenerator housings of annular cross section surrounding the cylinders of the engine, said heater head comprising arcuately shaped primary manifolds connected to the cylinder tops, arcuately shaped secondary manifolds connected to the regenerator housing tops, and a plurality of equally shaped heater tubes connecting said primary and secondary manifolds which when mounted together form two coaxially disposed circular tube row connections.
2. Description of the Prior Art
The U.S. Pat. No. 4,261,173 shows a hot gas engine heater head of known design in which the primary manifolds together form a complete circular tube row connection and in which the secondary manifolds together form another complete circular tube connection. The manifolds of each cylinder-regenerator housing unit of the known four-cylinder engine extend through a common 90 degree angular section. This involves radial gaps through the heater head between the adjacent manifolds. Such gaps may increase due to thermal deformations and they will involve loss of heat.
In case of uneven heat transfer to the heater head one cylinder-regenerator unit may be exposed to greater heat than the other units. This will result in a lower average heater head temperature because the temperature is governed by the peak value. A lower average hot gas temperature will cause a decrease of the engine efficiency.